/**
 * Copyright (C) 2015 The Gravitee team (http://gravitee.io)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.gravitee.gateway.core.loadbalancer;

import io.gravitee.gateway.api.endpoint.Endpoint;
import java.util.Collection;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author David BRASSELY (david.brassely at graviteesource.com)
 * @author GraviteeSource Team
 */
public class RoundRobinLoadBalancer extends LoadBalancer {

    private final AtomicInteger counter = new AtomicInteger(0);

    public RoundRobinLoadBalancer(Collection<Endpoint> endpoints) {
        super(endpoints);
    }

    @Override
    public Endpoint nextEndpoint() {
        int size = endpoints.size();
        if (size == 0) {
            return null;
        }

        return endpoints.get(Math.abs(counter.getAndIncrement() % size));
    }

    @Override
    public String toString() {
        return "RoundRobinLoadBalancer";
    }
}
